Gage-marking device



Feb. 11, 1947. B, c, N; JR 2,415,434

I GAUGE-MARKING DEVICE Filed July 8, 1944 INVENTOR. 544 75,? 6. Meals/v, L/e.

Patented Feb. 11, 1947 UNITED STATES PATENT OFFICE GAGE-MARKING nEvIoE Baxter 0. Madden, Jr., San- Francisco, Calif. Application July 8, 1944, Serial No. 544,125

Claims. (01. 101-5) (Granted under the act of March 3, 1883, as-

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to marking devices, having special reference to a device for facilitatin the marking of test specimens.

Recent investigations have indicated the desirability of obtaining elongation measurements in gage lengths of the order of one quarter inch or less, requiring a considerable number of graduations on each specimen. These graduations have heretofore either been laid off on the specimen and ruled with pen or pencil or transferred from. a graduated transparent strip to a sensitized' photographic coating previously applied to the specimen, either procedure requiring a considerable expenditure of time and effort.

It is therefore an object of this invention to provide a device whereby one may quickly and easily apply a series of accurately spaced graduations on a test piece, to the end that after stretching, forming, or pulling to failure, the

elongation of the specimen in a gage length of the order of the space between graduations or any multiple thereof up to the capacity of the device may be conveniently measured. v

Moreover it is wellknown that test specimens, in order to give accurate results, must bewithout deformations in, or other mechanical injury to the material of the test piece. For this reason any graduations which may be applied to the test piece must be added to the surfaceand not cut into it.

It is therefore another object of the invention to provide a device which will apply the markings in the form of ink lines to the surface of the test specimen.

Since specimens to be tested may come in a variety of thicknesses, it is another object of the invention to so construct and arrange the device embodying the present invention that different thicknesses of specimens may be marked without making any adjustments in the mech-' anism.

That these and other objects and "advantages are attained will be evident from the following description, taken in conjunction with the drawing, wherein, the single figure is a perspective view of my improved marker shown open as it place ready to be appears with a specimen in marked.

Referring to the drawing, a base ill has a bottom member l2 with side pieces I4 and end pieces l6 fastened respectively to the edges and ends ofamended April 30, 1928' 370 O. G. 757),.

, 2 the base by screws 18, thereby forming a troughlike. bed in which a carriage 2!! is endwise slidable.

Along one edge, the carriage 20 has a rack 22 permanently secured thereto by any suitable means, and at the ends of the carriage the clamp blocks 24 and 25 are secured by screws 28, the block v being cut out on the underside as at 3!! to admit a test pieceof the longest crosssectional area which is to be tested. A thumb screw 32 extends through the front clamp block 24 while a hollow set screw 34' extends through the rear block 25 both screws preferably being tightened to hold the test piece 36.

Secured to the sides M- of the bed it! by screws 38 are a pair of upright bearing brackets 40 on the upper ends of which the gear box 42' is pivotally supported. Gear box 42 consists of a bottom member 44 and side members 45 and 41 and held together by screws 48.

Shafts 5t, 52 and 54 have ro-tativebearing in the side members 45 and 41. Shaft 54 extends throughboth the bearing brackets 40 andthe side members 46 and 4?, whereby the gear box 42 is adapted to swing about the axis of the shaft 54.

Securely mounted on the right hand end of theshaft 5 3 is a gear 55 which is in constant mesh with the rack 22, whereby sliding the carriage back and forth on the base It! rotates the shaft 54 in one direction or the other, whereby the shaft 54 may conveniently be referred to as the drive shaft. Collars 58 and 51'! are respectively secured to the shafts and 52 so as to abut the side member 41 therebylimiting axial movement of the shafts to the right.

Gears B2, 64 and 66 are respectively secured to the shafts 58, 52 and 54 abutting the side member 46, thereby limiting axial movement of the shafts to the left. A marking wheel 58 is fast on the shaft 50 substantially midway of its ends, whereby the shaft 50 may preferably be called the driven shaft or the marker shaft, and the shaft 52 be called the intermediate shaft or the idler shaft. Obviously, if the carriage 2G is moved endwise on the base ii], the marking wheel 68 will rotate in the same direction as the gear 56 is rotated by the rack 22.

Since, for proper operation, it is required that the circumferential movement of a point on the. periphery of the marking wheel 38 be exactly the same as the linear distance through which the carriage 2!! moves, the ratio of the pitch diameter of the gear 56 to the outside diameter of the markingwheel 68' must equal the ratio of 3 the gear 65 to the gear 62. This condition is met in the exemplification shown by marking all of the gears of the same pitch diameter, and makin the outside diameter of the marking wheel the same as the pitch diameters of the ears.

For illustrative purposes only, the m k wheel, in the embodiment shown, has teeth circumferentially spaced one sixteenth inch apart; Larger or smaller spacing may, of course, be provided as the case in hand may require.

A light spring has one end fastened to the Side member IA of the base and the other end to the side member 46 of the gear box, whereby the gear box is normally held by the spring in the inoperative position shown in full lines in the drawing. The operation of the device is substantially as follows:

The marking wheel 68 is first inked. A thin film of printers ink is spread over one surface of a piece of rubber, or rubber substitute, approximately one eighth inch thick and of a length and width somewhat greater than the surface to be marked. A roller, similar to that employed in taking fingerprints may be used for this purpose. The rubber is laid on the carriage between the clamp blocks 24 and 26 covering the area to be occupied by the specimen which is to be marked, inked side up; the gear box 42 is swung forward on its pivotal axis until the marking wheel comes into Contact with the inked rubber as seen in phantom lines in the drawing; a light pressure is applied to the gear box with one hand to maintain contact of the marking wheel with the inked rubber, while the knob of the thumb screw 32 is. grasped with the other hand and moved throughout the full travel of the carriage. Both hands may now be released from the device and the inking rubber removed. Subsequent inkings of the marking wheel require only that the residual ink on the rubber be spread evenly again. Additional ink need be added only after some ten to fifteen specimens have been marked. The rubber inking pad should be cleaned of ink after each days use.

The specimen is now clamped to the carriage 20 by the set screws 32 and 34, a wrench being used for the latter; the carriage 20 is brought to one end of its travel; the marking 'wheel is brought into contact with the specimen as shown in phantom; the carriage is then moved to the opposite end of its travel. Both hands are now released, the set screws loosened, and the marked specimen removed from the device, care being taken to avoid smearing the marks until they are fully dry.

In cases where the specimen is warped, a piece of sheet rubber approximately one thirty-second inch thick and approximately forty durometer A hardness may preferably be inserted beneath the specimen for its entire length. The manner in which the gear box 42 is pivotally supported automatically adjusts the marking wheel for the increased thickness when the sheet rubber is laid under the specimen as it will also compensate for specimens of different thicknesses.

After stretching, forming, or pulling to failure, the elongation of the specimen in a gage length of one sixteenth inch or any multiple thereof up to the capacity of the machine may be conveniently measured. Gage marks of other measurement may be obtained by appropriately spacing the teeth of another marking wheel.

. Having shown and described an embod m n 7 of my invention, I claim:

1. In a device for marking test specimens of the character described, a base, a carriage endwise slidable on said base, a rack extending along one side of said carriage secured thereto for movement therewith, a pair of clamp blocks, one fast on each end of said carriagev and grooved on "the underside to receive the test" specimen, a clamp screw extending through the top of each said block into said groove, bearing brackets extending upwardly from said base, a shaft extending transversely of said base and having rotative bearing in said brackets, the ends of said shaft extending through and slightly beyond said bearings, a gear box pivotally supported on said extendin ends, a second and a third shaft both parallel to the first shaft and having their axes in the same plane and having rotative bearing in said gear box, a gear fast on the third shaft, a gear fast on the second shaft in mesh with'rthe gear on the third shaft, a gear fast on the first shaft in mesh with the gear on the second shaft, another gear fast on the first shaft in mesh with said rack, all four of the said gears being of equal pitch diameter, and a marking wheel faston the third shaft substantially mid- Way'of the ends having circumferentially equally spaced teeth brought to substantially a sharp edge and havin an outside diameter equal to the pitch diameter of the said gears.

2;;In a device for marking test specimens of the character described, a base, a carriage'slidable on said base, a rack extending along said carriage secured thereto for movement therewith, a pair of clamps, one fast on each end of said carriage and adapted to receive and hold the test specimen, a clamp screw in each clamp for fastening said specimen, bearing brackets extending from said base, a shaft extending crosswise of said base and having rotative bearing in said brackets, the ends of said shaft extending through and slightly beyond said bearings, a gear box pivotally supported on said extending ends, a second and a third shaft both parallel to the first shaft and having rotative bearing in said gear box, a gear fast on the third shaft, a gear fast on the second shaft in mesh with the gearon the third shaft, a gear fast on the-first shaft in mesh with the gear on the second shaft, another gear fast on the first shaft in mesh with said rack, the two gears on the first shaft and the gear on the third shaft being of equal pitch diameter, and a marking wheel fast on the third shaft substantially midway of the ends having circumferentially equally spaced teeth brought to substantially a sharp edge and having an outside diameter equal to the pitch diameter of the said gears.

.3. In a device for marking test specimens of the character described, a base, a carriage slidable on said base, a rack extending along said carriage secured thereto for movement therewith, clamping means fast on said carriage-and adapted to receive and hold the test specimen,

bearing supports on said base, a driving shaft with;

axis normal to the movement of said carriage having rotative bearings in said supports, a gear.

having rotative bearing in said gear box, a gear:

fast on the driven shaft, a gear fast on the idler shaft in mesh with the, gear on'the driven shaft,

a gear fast on the driving shaft in mesh w ithi 5 the gear on the idler shaft, anothergear fast on the driving shaft in mesh with said rack, the gear which is in mesh with the rack and the gear on the driven shaft being of equal pitch diameter, and a marking wheel fast on the driven shaft substantially midway of the ends having circumferentially equally spaced teeth brought to substantially a sharp edge and having an outside diameter equal to the pitch diameter of the gear on the driven shaft.

4. In a device for marking test specimens of the character described, a base, a carriage movable on said base, a rack extending along one side of said carriage secured thereto for movement therewith, clamping means fast on said carriage and adapted to receive and hold the test specimen, bearing supports on said base, a driving shaft extending crosswise of said rack and having rotative bearing in said supports, a gear boxpivotally supported to swing about the driving shaft axis, a driven shaft spaced apart from the driving shaft and having rotative bearing in said gear box, a driven gear fast on the driven shaft, a driving gear fast on the driving shaft, rotation transmitting means connecting the two said gears for rotation at the same speed and in the same direction, a rack engaging gear fast on said driving shaft 111; mesh with said rack, a marking wheel fast on the driven shaft substantially midway of the ends having circumferentially equally spaced teeth brought to sub: stantially a sharp edge, the ratio of the pitch diameter of the rack engaging gear to the outside diameter of the marking wheel being the same as the ratio of the pitch diameter of the driving gear to the pitch diameter of the driven gear.

5. In a device for marking test specimens of the character described, a base, a carriage supported on said base and movable. with respect thereto, a rack fast on said carriage for endwise movement therewith, clamping means on said carriage to hold said specimen to said carriage, a driving shaft rotatably supported on said base, a rack engaging gear on said driving shaft in mesh with said rack, a marking wheel shaft, a marking wheel on said shaft, having teeth brought to substantiallya sharp edge, means supported on said base having journal bearings for said marking wheel shaft, means permitting said journal bearings to be moved toward or away from said carriage without changing the depth of engagement of the rack engaging gear in the rack, and rotation transmitting means connecting the two said shafts for rotation in the same direction, the ratio of rotation of the driving shaft to the marking wheel shaft being equal to the ratio of the pitch diameter of the rack gear to the outside diameter of the marking wheel.

BAXTER C. MADDEN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

